This disclosure relates generally to a customer replaceable unit (CRU) or a field support engineer (tech rep) replaceable unit (ERU) for a printing machine. More particularly, the present disclosure relates to monitors for customer replaceable units and engineer replaceable units.
In a typical electrographic or xerographic copying or printing process, a charge retentive surface such as a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is selectively exposed to light to dissipate the charges thereon in areas subjected to the light. This records an electrostatic latent image on the photoconductive member. After the electrostatic latent image is recorded on the photoconductive member, the electrostatic latent image is rendered visible by bringing one or more developer materials into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules either to a donor member or to a latent electrostatic image on the photoconductive member. When attracted to a donor member, the toner particles are subsequently deposited on the latent electrostatic images. The toner powder image is then transferred from the photoconductive member to a final substrate or imaging media. The toner particles forming the toner powder images are then subjected to a combination of heat and/or pressure to permanently affix the powder images to the substrate.
A fuser assembly is commonly used to heat the toner material and cause it to fuse to the substrate. The assembly includes a fuser roll that rotates around an axis as the substrate is drawn between it and a pressure roll. Heat is applied to the toner material via the fuser roll during this drawing process. Fuser rolls typically operate at temperatures up to approximately 200° C.
Many machines have replaceable sub-assemblies. Printing machines, for example, may have a number of replaceable sub-assemblies such as a fuser print cartridge, a toner cartridge, or an automatic document handler. These subassemblies may be arranged as unit called a cartridge, and if intended for replacement by the customer or machine owner, may be referred to as a CRU. Examples of a CRU may include a printer cartridge, a toner cartridge, or a transfer assembly unit. It may be desirable for a CRU design to vary over the course of time due to manufacturing changes or to solve post-launch problems with either the machine, the CRU, or a CRU and machine interaction. Further, design optimizations may be recognized subsequent to design launch and machine sale that a relatively simple code update might realize. However, solving these problems, or providing optimization updates, generally requires a field service call to accomplish.
U.S. Pat. No. 6,016,409 to Beard et al. discloses a fuser module which includes an electronically readable memory permanently associated therewith. The control system of the printing apparatus reads out codes from the electronically-readable memory at installation to obtain parameters for operating the module, such as maximum web use, voltage and temperature requirements, and thermistor calibration parameters.
The fuser roll that is a component of the fuser module may be replaced independently of the other fuser module components. Accordingly, it would be advantageous to have a monitor installed on the fuser roll, and not as part of the entire fuser module assembly. However, the hostile environment to which fuser rolls are subjected, 200° C., exceeds the limits of conventional monitor devices, generally less than 125° C.